The move, which will affect 66 employees and cost San Diego-based Arena $3.8m, follows the US Food and Drug Administration’s (FDA) rejection of the drug in October on concerns about tumours in rats during preclinical trials.
CEO Jack Lief said: "This workforce reduction strengthens our financial position by focusing our resources on the prioritized programs that we believe have the greatest potential to deliver value."
He also said Arena is working to address the FDA's concerns, explaining that: “The first issue relates to the diagnostic uncertainty in the classification of mammary masses in female rats,” adding that the firm has called in five independent pathologists to reassess the finding.
He also said Arena is planning experiments to further test the theory that lorcaserin causes mammary tumours in rats by increasing prolactin as well as work to address FDA questions about the drug's abuse potential.
"Our ongoing discussions with the FDA reflect our commitment to addressing the issues raised in the CRL to the agency's satisfaction," Lief said. "We now have a greater understanding of the FDA's position as we move forward with our plans to resubmit the lorcaserin NDA."